Soundgarden's masterful album 'Superunknown' turned 20 this year, and throughout 2014, the landmark record has been celebrated for its accomplishments. In a new retrospective posted by Spin, the members of Soundgarden and others involved with 'Superunknown' recall the album's creation. Even more fascinating, the article recounts in-studio visits by members of Nirvana, Pearl Jam, the Smashing Pumpkins, Queens of the Stone Age and even Johnny Cash while 'Superunknown' was being recorded.

The retrospective of 'Superunknown' is presented via an oral history, with Soundgarden musicians Chris Cornell, Kim Thayil and Ben Shepherd, along with Pearl Jam members and 'Superunknown' contributors telling the story.

For any Soundgarden fan, the full article is a must-read, but perhaps the most interesting part documents the cavalcade of brilliant musicians who hung out at Seattle's Bad Animals studio while 'Superunknown' was coming together.

"I remember Josh Homme coming by and I remember Billy Corgan coming by," says Kim Thayil. "Pearl Jam were hanging out. I remember Josh Homme really wanting to play ping-pong after Adam Kasper and I had just eaten a lot of Indian food. So we were all kind of sluggish and bloated and he was like, 'Man, let’s play ping-pong!' and I was like, 'If I play ping-pong, it needs to be against someone equally sluggish and bloated.' I remember that conversation like, 'Come on you guys, let’s play!” and I was like, “Dude, I can’t move.'"

'Superunknown' assistant engineer Adam Kasper adds, "Corgan was in town and something happened with their tour bus. They couldn’t make it from Portland because of a storm, so they were gonna borrow some of the gear we had, and he just sat there and checked out what we were doing. Other people would come by. The Nirvana dudes would stop in. I remember the Breeders were around a lot. Johnny Cash was pretty amazing. He was around there for awhile; there was a [Willie Nelson] tribute record being done and so he was in Seattle, just kind of hanging out in the studio. A lot of people would come through and just vibe out on the scene."